Nervous tissue

Question 1

What two systems play the most important roles in maintaining homeostasis?

Answer 1

Nervous and endocrine system

Question 2

central nervous system (CNS) consists of:

Answer 2

brain and spinal cord

Question 3

peripheral nervous system (PNS) consists of:

Answer 3

all nervous tissue outside the CNS.

Question 4

Basic functions of the Nervous System

Answer 4

Sensory (input), Integrative (process),
and Motor (output)

Question 5

What two nervous systems are in the motor division of the PNS

Answer 5

Somatic and autonomic nervous system

Question 6

What two senses are in the sensory division of the PNS?

Answer 6

Somatic senses and special senses

Question 7

Nerve cell (neuron) characteristics

Answer 7

Electrically excitable
* Dendrites: Main receiving or input region.
* Cell body
* Axon: Conducts nerve impulses toward another neuron, a muscle fiber, or a gland cell.

Question 8

Different neuron structures and how are they divided

Answer 8

classified based on the number of processes extending from the cell body
Multipolar,bipolar and unipolar

Question 9

Sensory/Afferent neurons

Answer 9

Conveys information to the CNS

Question 10

Motor/Efferent neurons

Answer 10

Conveys action potential from the CNS

Question 11

Interneurons/Association neurons

Answer 11

o Located in the CNS
o Process sensory information and elicit motor response

Question 12

Neuroglia

Answer 12

• Not electrically excitable
• Make up about half the volume of the nervous system, think of connective tissue of nervous system

Question 13

Neuroglia in the CNS include:

Answer 13

• Astrocytes
• Oligodendrocytes
• Microglia
• Ependymal cells

Question 14

Neuroglia in the PNS include:

Answer 14

• Schwann cells
• Satellite cells

Question 15

myelin sheath

Answer 15

coat of lipids and proteins
Myelination insulates the
axon and increases the rate
of conduction of nerve
impulse

Question 16

Myelin sheath is produced
by:

Answer 16

• oligodendrocytes in CNS
• Schwann cells in PNS

Question 17

Gray Matter vs. White Matter

Answer 17

White matter is myelinated and grey matter is un-myelinated

Question 18

Ganglia

Answer 18

refers to a cluster of neuronal cell bodies located
in the PNS

Question 19

Nerve Tract

Answer 19

bundle of axons specifically located in the
CNS

Question 20

resting membrane potential

Answer 20

–70 mV

Question 21

all-or-none principle

Answer 21

if a stimulus is
strong enough to generate an action potential, the
impulse generated is of a constant size.

Question 22

Continuous Conduction

Answer 22

Nerve impulse conduction
that travels sequentially along the entire membrane.
Slower conduction rate.

Question 23

Saltatory conduction

Answer 23

nerve impulse “leaps” along a myelinated axon from one node of Ranvier to the next.
* Myelinated axons conduct impulses faster than
unmyelinated axons

Question 24

Threshold of nervous system action potential generation

Answer 24

-55 mV
It is reached by latent collection of Na ions in axon

Question 25

Action potentials traveling is called?

Answer 25

propagation

Question 26

Factors That Affect Propagation Speed

Answer 26

Axon diameter-larger=faster Amount of myelination- more=faster Temperature- hotter=faster

Question 27

A synapse

Answer 27

the junction between neurons or between a neuron and an effector

Question 28

Electrical Synapse

Answer 28

Gap junctions connect cells and allow the transfer of information to synchronize the activity of a group of cells

Question 29

Chemical Synapse

Answer 29

One-way transfer of information using chemical messengers from a presynaptic neuron to a postsynaptic neuron

Question 30

Neurotransmitter

Answer 30

released at a synapse from a presynaptic neuron into the synaptic cleft and then binds to receptors on the plasma membrane of the postsynaptic neuron.

Question 31

Two types of neurotransmitters

Answer 31

* Excitatory postsynaptic potentials- A depolarizing postsynaptic potential * Inhibitory postsynaptic potentials- A hyperpolarizing postsynaptic potential

Question 32

Neurotransmitter is removed in three ways:

Answer 32

1. Diffusion of molecules 2. Enzymatic degradation 3. Uptake by cells (recycling)

Question 33

Summation

Answer 33

If several presynaptic end bulbs release their neurotransmitter at about the same time, the combined effect may generate a nerve impulse due to summation

Question 34

Neurotransmitter types

Answer 34

Two main groups I. Small molecule neurotransmitters II. Neuropeptides

Question 35

Small molecule neurotransmitters

Answer 35

1) Acetylcholine 2) Amino acids 3) Biogenic amines 4) ATP 5) Gases

Question 36

Neuropeptide Neurotransmitters

Answer 36

1. Long chains (3 to 40 amino acid structure) Examples * Substance P * Enkephalins * Endorphins * Dynorphins * Angiotensin II * Cholecystokinin (CCK)

Question 37

Plasticity

Answer 37

the capability to change based on experience

Question 38

In the CNS, there is little or no repair due to:

Answer 38

* Inhibitory influences from neuroglia, particularly oligodendrocytes * Absence of growth-stimulating cues that were present during fetal development * Rapid formation of scar tissue